LITERATURE UNDER MONGOLS 227 nevertheless obtained a good education and travelled all over Persia. As already mentioned, he was among the fortunate few who escaped death at Merv. His flight across Northern Persia ended at Mosul, where in A.D. 1244 he completed his Mujam-ul-Buldan^ or "Dictionary of Countries," This work has been made available to the European student by the gifted Frenchman Barbier de Meynard, and has been among my most valued books of reference. Nasir-u-Din, the Philosopher and Man of Science.— Among the courtiers of the last Grand Master of the Assassins was Nasir-u-Din, the famous philosopher of Tus, who had been kidnapped to serve as his instructor and adviser, and who persuaded his master" to surrender to the Mongols. He was treated with much respect by Hulagu Khan, over whom he exercised unbounded influence, and it was chiefly his advice which induced the Mongol Prince to undertake the final advance on Baghdad. His range included religion, philosophy, mathematics, physics, and astronomy, on which subjects he wrote at great length, and one of his chief claims to fame is that he persuaded Hulagu to found the celebrated observatory at Maragha. The Sufis or Mystics.—Among the most famous poets of Persia were the mystics or Sufis, " Wearers of Wool," as they are termed, and this spirit of mysticism has per- meated Persian literature and the Persian mind to a remarkable extent.1 Its origin is hard to trace. Possibly it is a modern form of ancient philosophies, more especi- ally of Neo-Platonism and Manicheanism. Others hold that it is a reaction of Aryanism against the formalism of the Moslem religion, and, again, the philosophy of India has been looked on as its fountain-head. The true founder of the system is believed to have been Abu Said ibn Abul Khayr, who was born in Khorasan towards the end of the tenth century of our era. When isked to explain his doctrine, he replied, " What thou b.ast in thy head, i.e. thy ambitions, resign ; what thou nearest in thy hand throw away ; and whatsoever cometh 1 Nizami and Attar, of the pre-Mongol period, were mystical poets.